Surgical drainage bags of the kind used by patients who have had colostomy or ileostomy operations are commonly called ostomy bags. They are used to receive waste material from the stoma of the patient. Flatus will, of course, also pass into the bag and for this reason such bags are commonly provided with venting means to enable the flatus to escape. It is known to provide the venting means with a filter to remove undesirable odours. For exanple, an ostomy bag with a venting means is described in published United Kingdom Patent Specification No. 15964396.
An object of the present invention is to provide an improved filter for such a bag and a bag with a filter which can easily be replaced by the patient as desired and which is adequately leakproof.